This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Cocaine abuse and addiction continue to be a major problem worldwide with grave medical and socioeconomic consequences, and few effective therapies exist to treat this brain disorder. A prevailing theory in the neurobiology of addiction is that repeated cocaine exposure imposes persistent neurochemical and molecular changes, e.g. altered gene expression, in the reward circuitry. The goal of this project is to comprehensively investigate gene expression dysregulation within the mesocorticolimbic reward circuit that may mediate compulsive cocaine taking, using a nonhuman primate model of moderate and excessive cocaine self-administration.